This invention relates but is not unique to the field of radio paging and alarm simulcast transmission systems using Digital Data, Tone Only or Tone and Voice formats. To accomplish this, the invention uses direct numeric synthesis technology which digitally modulates radio signals with the desired numeric information, therefore data or voice transmission systems can now be built with unprecedented accuracy, simplicity and economic performance. Numeric signal synthesis technology solves many problems like modulation accuracy, variable data rate intolerance as well as bandwidth control by using signal shaping techniques.
The contributions of the Number Controlled Modulated Oscillator (NCMO) in the communications and surveillance fields are many, and its contribution to this data communications system design due to its precision signals has permitted the application of numeric syntheses technology to these communications formats. Another of the most desirable features of the present invention is the high speed capabilities of its transmission.